I have to design a band reject filter using two capacitors, two resistors and a load resistor of 1kOhm.

I already figured out the appropriate circuit and had derive the transfer function of the filter.

I had chose the values for the capacitors, C = 0.01uF and the value of load resistor is 1kOhm.

Now I want to find the values of R, when the centre frequency is 30kHz/60000pi rads-1.

To find the R, all I need to do is substitute the value of C, RL, omega=60000pi and the magnitude |H(s)| = 0.

The problem is I obtained the values of R, and when I simulate the circuit, the centre frequency is not at 30kHz(I've tried all the values too)

I also checked the transfer function derived a few times and so far found no mistakes, I think.

So, do anyone have any idea why is the obtained values of R is incorrect? Maybe I might have missed a few important points.

Thank you in advanced!